Role of Cardiac Computed Tomography for Etiology Evaluation of Newly Diagnosed Heart Failure with Reduced Ejection Fraction

Feasibility of the Threshold-Based Quantification of Myocardial Fibrosis on Cardiac CT as a Prognostic Marker in Nonischemic Dilated Cardiomyopathy

OBJECTIVE

This study investigated the feasibility and prognostic relevance of threshold-based quantification of myocardial delayed enhancement (MDE) on CT in patients with nonischemic dilated cardiomyopathy (NIDCM).

MATERIALS AND METHODS

Forty-three patients with NIDCM (59.3 ± 17.1 years; 21 male) were included in the study and underwent cardiac CT and MRI. MDE was quantified manually and with a threshold-based quantification method using cutoffs of 2, 3, and 4 standard deviations (SDs) on three sets of CT images (100 kVp, 120 kVp, and 70 keV). Interobserver agreement in MDE quantification was assessed using the intraclass correlation coefficient (ICC). Agreement between CT and MRI was evaluated using the Bland-Altman method and the concordance correlation coefficient (CCC). Patients were followed up for the subsequent occurrence of the primary composite outcome, including cardiac death, heart transplantation, heart failure hospitalization, or appropriate use of an implantable cardioverter-defibrillator. The Kaplan-Meier method was used to estimate event-free survival according to MDE levels.

RESULTS

Late gadolinium enhancement (LGE) was observed in 29 patients (67%, 29/43), and the mean LGE found with the 5-SD threshold was 4.1% ± 3.6%. The 4-SD threshold on 70-keV CT showed excellent interobserver agreement (ICC = 0.810) and the highest concordance with MRI (CCC = 0.803). This method also yielded the smallest bias with the narrowest range of 95% limits of agreement compared to MRI (bias, -0.119%; 95% limits of agreement, -4.216% to 3.978%). During a median follow-up of 1625 days (interquartile range, 712-1430 days), 10 patients (23%, 10/43) experienced the primary composite outcome. Event-free survival significantly differed between risk subgroups divided by the optimal MDE cutoff of 4.3% (log-rank P = 0.005).

CONCLUSION

The 4-SD threshold on 70-keV monochromatic CT yielded results comparable to those of MRI for quantifying MDE as a marker of myocardial fibrosis, which showed prognostic value in patients with NIDCM.

Coronary Computed Tomography Angiography: Beyond Obstructive Coronary Artery Disease

Nowadays, coronary computed tomography angiography (CCTA) has a role of paramount importance in the diagnostic algorithm of ischemic heart disease (IHD), both in stable coronary artery disease (CAD) and acute chest pain. Alongside the quantification of obstructive coronary artery disease, the recent technologic developments in CCTA provide additional relevant information that can be considered as "novel markers" for risk stratification in different settings, including ischemic heart disease, atrial fibrillation, and myocardial inflammation. These markers include: (i) epicardial adipose tissue (EAT), associated with plaque development and the occurrence of arrhythmias; (ii) late iodine enhancement (LIE), which allows the identification of myocardial fibrosis; and (iii) plaque characterization, which provides data about plaque vulnerability. In the precision medicine era, these emerging markers should be integrated into CCTA evaluation to allow for the bespoke interventional and pharmacological management of each patient.

A retrospective study on the clinical significance of cardiac computed tomography in heart failure patients with preserved ejection fraction

Background

This study investigated the correlation between cardiac function parameters by cardiac computed tomography (CT) and the clinical outcomes of heart failure patients with preserved ejection fraction (HFpEF) to provide experimental data for the diagnosis of HFpEF.

Methods

A total of 157 HFpEF patients admitted to our hospital from January 2017 to January 2019 were retrospectively analyzed. The patients were divided into event and non-event groups according to the occurrence or absence of adverse events. Cardiac function parameters, such as the left ventricular (LV) end-diastolic volume (LVEDV) and LV end-diastolic volume index (LVEDVI), were obtained via CT scan. Also, the N-terminal-pro hormone b-type natriuretic peptide (NT-proBNP) levels in patients' serum were measured using an enzyme linked immunosorbent assay (ELISA) kit, and echocardiographic parameters such as LV posterior wall thickness (LVPWT) were also recorded. Further, Cox regression was employed to analyze factors associated with the clinical outcomes.

Results

Compared with patients in the non-event group, the left ventricular end-diastolic mass (LVM), LVEDVI, left ventricular end-systolic volume index (LVESVI), left atrial end-diastolic volume index (LAEDVI), and left atrial end-systolic volume index (LAESVI) were significantly increased, and the left ventricular total emptying fraction (LVTEF) and left atrial total emptying fraction (LATEF) were markedly decreased in the event group patients. Also, the E/e' and LAEDVI were related factors affecting the clinical outcomes of HFpEF patients. The above indicators displayed a significant predictive for the clinical outcomes of HFpEF patients.

Conclusions

Several cardiac function measures, including LAEDVI, are factors associated with the clinical outcomes of HFpEF patients.

The chronic coronary syndrome—Heart failure roundabout: A multimodality imaging workflow approach

Heart failure (HF) is a complex syndrome of considerable burden with high mortality and hospitalization rates. Approximately two-thirds of patients with HF have ischemic etiology, which makes crucial the identification of relevant coronary artery disease (CAD). Moreover, patients with chronic coronary syndrome (CCS) can first show signs of dyspnea and left ventricular (LV) dysfunction. If establishing a diagnosis of HF and consequent management is clear enough, it will not be the same when it comes to recommendations for etiology assessment. Ischemic heart disease is the most studied disease by cardiac multimodality imaging with excellent diagnostic performance. Based on this aspect, the high prevalence of CAD, the worst outcome—HF patients should undergo a diagnostic work-up using these multimodality imaging techniques. The aim of this mini-review is to provide insights on multimodality imaging for diagnosing CCS in patients with new onset of HF and propose a diagnostic work-up based on current international studies and guidelines.

Clinical applications of cardiac computed tomography: a consensus paper of the European Association of Cardiovascular Imaging-part II

Cardiac computed tomography (CT) was initially developed as a non-invasive diagnostic tool to detect and quantify coronary stenosis. Thanks to the rapid technological development, cardiac CT has become a comprehensive imaging modality which offers anatomical and functional information to guide patient management. This is the second of two complementary documents endorsed by the European Association of Cardiovascular Imaging aiming to give updated indications on the appropriate use of cardiac CT in different clinical scenarios. In this article, emerging CT technologies and biomarkers, such as CT-derived fractional flow reserve, perfusion imaging, and pericoronary adipose tissue attenuation, are described. In addition, the role of cardiac CT in the evaluation of atherosclerotic plaque, cardiomyopathies, structural heart disease, and congenital heart disease is revised.

Multimodal Imaging and Biomarkers in Cardiac Amyloidosis

Amyloidosis is a progressive infiltrative disease instigated by the extracellular deposition of amyloid fibrils in various organs such as the heart, kidney, and peripheral nerves. Cardiac amyloid deposits cause restrictive cardiomyopathy, leading to a poor prognosis in systemic amyloidosis. The most common etiologies of cardiac amyloidosis (CA) are immunoglobulin light chain deposits (AL-CA) and misfolded transthyretin deposits (ATTR-CA). In recent years, many developments have been accomplished in the field of diagnosis and treatment of CA. At present, ATTR-CA can be noninvasively diagnosed if the following two conditions are fulfilled in the setting of typical echocardiographic/cardiac MRI findings: (1) grade 2 or 3 myocardial uptake in bone scintigraphy confirmed by SPECT and (2) absence of monoclonal protein confirmed by serum-free light chain assay, and serum/urine protein electrophoresis with immunofixation test. Effective therapies are evolving in both types of CA (tafamidis for ATTR-CA and immunologic treatments for AL-CA). Thus, early suspicion and prompt diagnosis are crucial for achieving better outcomes. In this review, we have summarized the role of multimodal imaging (e.g., echocardiography, cardiac MRI, and bone scintigraphy) and biomarkers (e.g., troponin, BNP) in the diagnosis, risk stratification, and treatment monitoring of CA.

Diagnostic accuracy of coronary computed tomography angiography in ischemic workup of heart failure: a meta-analysis

Aim: The role of coronary computed tomography angiography (CCTA) in evaluating the etiology of heart failure with reduced ejection fraction (HFrEF) is unclear. This is a meta-analysis assessing the pooled diagnostic accuracy of CCTA in diagnosing significant coronary artery disease in HFrEF. Materials & methods: Electronic databases were searched for studies comparing CCTA with invasive coronary angiography in HFrEF. A random-effects model meta-analysis was conducted. Results: Five studies comprising 269 patients were included. On patient-based analysis, pooled sensitivity and specificity of CCTA were 0.99 (95% CI: 0.94-1.00) and 0.94 (95% CI: 0.90-0.97), respectively. On segment-based analysis, pooled sensitivity and specificity were 0.74 (95% CI: 0.67-0.80) and 0.99 (95% CI: 0.98-0.99), respectively. Conclusion: CCTA has excellent diagnostic accuracy in diagnosing significant coronary artery disease in newly diagnosed HFrEF.

Synthetic Extracellular Volume Fraction Derived Using Virtual Unenhanced Attenuation of Blood on Dual-Energy Contrast-Enhanced Cardiac CT in Nonischemic Cardiomyopathy

Background: Current methods for calculating myocardial extracellular volume fraction (ECV) require blood sampling to obtain serum hematocrit. Synthetic hematocrit and thus synthetic ECV may be derived using unenhanced attenuation of blood. By use of virtual unenhanced (VUE) attenuation of blood, contrast-enhanced dual-energy CT (DECT) may allow synthetic ECV calculations without unenhanced acquisition. Objective: To compare synthetic ECV using synthetic hematocrit derived from VUE images versus conventional ECV using serum hematocrit, both obtained by contrast-enhanced DECT, using MRI-derived ECV as reference. Methods: This retrospective study included 51 patients (26 men, 25 women; mean age 59.9 ± 15.6 years) with nonischemic cardiomyopathy who, as part of an earlier prospective investigation, underwent equilibrium-phase contrast-enhanced cardiac DECT and cardiac MRI, with serum hematocrit measured within 6 hours of both tests. A separate retrospective sample of 198 patients who underwent same-day contrast-enhanced thoracic DECT for suspected pulmonary embolism and serum hematocrit measurement was identified to derive a synthetic hematocrit formula using VUE attenuation of blood by linear regression analysis. In the primary sample, two radiologists independently used DECT iodine maps to obtain conventional ECV using serum hematocrit and synthetic ECV using synthetic hematocrit based on the independently derived formula. Concordance correlation coefficient (CCC) was computed between conventional ECV and synthetic ECV from DECT. Conventional ECV and synthetic ECV from DECT were compared with MRI-derived ECV in Bland-Altman analyses. Results: The linear regression formula for synthetic hematocrit in the independent sample was: synthetic hematocrit = 0.85 x (VUE attenuation of blood) - 5.40. In the primary sample, conventional ECV and synthetic ECV from DECT showed excellent agreement (CCC = 0.95). Bland-Altman analysis showed small bias of -0.44% with 95% limits of agreement from -5.10% to 4.22% between MRI-derived ECV and conventional ECV from DECT, and small bias of -0.78% with 95% limits of agreement from -5.25% to 3.69% between MRI-derived ECV and synthetic ECV from DECT. Conclusion: Synthetic ECV and conventional ECV from DECT show excellent agreement and comparable association with ECV from cardiac MRI. Clinical Impact: Synthetic hematocrit from VUE attenuation of blood may allow myocardial tissue characterization on DECT without inconvenience of blood sampling.